The lawyer who will stand before the court and argue that the law should be thrown out is likely to be Paul Clement, who served as U.S. solicitor general during the George W. Bush administration.

Clement’s law firm, Bancroft PLLC, was one of almost two dozen firms that helped sponsor the annual dinner of the Federalist Society, a longstanding group dedicated to advocating conservative legal principles. Another firm that sponsored the dinner, Jones Day, represents one of the trade associations that challenged the law, the National Federation of Independent Business.

Another sponsor was pharmaceutical giant Pfizer Inc, which has an enormous financial stake in the outcome of the litigation.